Elon Musk announced on X on Wednesday that xAI will release Grok 4.5, its latest large language model, to the public on July 9, calling it "an Opus-class model, but faster, more token-efficient and lower cost." Grok 4.5 first surfaced in private beta at Tesla and SpaceX in June, with Musk putting its early performance close to, and potentially above, Anthropic's Claude Opus, though none of his performance claims have been independently benchmarked yet. Grok 4.5 runs on a new 1.5-trillion-parameter foundation model known as V9, with supplemental training on data from the AI coding platform Cursor, which SpaceX is in the process of acquiring in a $60 billion deal. The release comes under the SpaceXAI banner, following Grok 4 launched in July 2025, and puts Grok 4.5 on a collision course with OpenAI, which is moving its GPT-5.6 models toward broader availability around the same period.